In the 3rd Generation Partnership Project (3GPP), in the Institute of Electrical and Electronics Engineers (IEEE), in the Radiocommunication Sector of the International Telecommunication Union (ITU-R) and other Standard Developing Organizations (SDO) there are currently discussed concepts for carrier aggregation or flexible spectrum utilization.
The general idea of carrier aggregation is to look for new ways of combining spectrum for a single radio access system. It is foreseen that in Long Term Evolution (LTE) and in particular in LTE-Advance (LTE-A) systems carrier aggregation will enable system bandwidths of up to 100 MHz thus leading to important improvement for available peak data rates. Other considerations or motivations for carrier aggregation is to enable an aggregation of small spectrum chunks into one big system bandwidth allowing for higher peak data rate and a better trunking efficiency.
When Time Division Duplex (TDD) and Frequency Division Duplex (FDD) systems are deployed in adjacent spectrum bands, typically there are needed large guard bands because TDD has UL and DL radio data transmission in the same band. According to known spectral arrangements for radio resources being usable for transmitting radio data these guard bands are necessary in order to protect from interference. However, these guard bands lead to a lot of idle spectrum that is wasted such that the efficiency of the overall telecommunication system is reduced.
FIG. 4 shows a within a diagram being spanned by a time-axis and a frequency-axis a known exemplary spectral arrangement 400 for radio resources when FDD and TDD systems are deployed together in adjacent frequency bands. The spectral arrangement 400 comprises a first radio resource 410, which is used for a FDD radio transmission in the UL direction. On the frequency scale the first radio resource 410 is spectrally separated with a guard band 415 both from a second radio resource 420a and a further second radio resource 420b. As can be seen from FIG. 4, the second radio resource 420a being assigned to a TDD UL transmission scheme and the further second radio resource 420b being assigned to a TDD DL transmission scheme are using the same frequency bandwidth. In order to reduce interference the radio resources 420a and 420b , which adjoin each other, are active in different time intervals of a predetermined full time interval T. The second radio resource 420a is active in a reduced time interval Tr. The further second radio resource 420b is active in a complementary reduced time interval Tc. Further, between the second radio resource 420a and the further second radio resource 420b and a third radio resource 430 being assigned to a FDD DL transmission scheme a further guard band 425 is provided in order to reduce interference between different radio transmissions.
There may be a need for providing a spectral arrangement for radio resources, which allows for an efficient usage of available radio resources such that the overall data rate within a radio telecommunication network can be increased.